Figure 1.

Cellular migration is dependent on cell intrinsic factors, as well as multiple signal inputs from the environment. (A) External signals such as chemokines are sensed by membrane-bound receptors on immune cells. The receptor-induced intracellular signaling reorganizes the actin cytoskeleton and the microtubule organizing center (MTOC) and activates integrins, resulting in adhesion to extracellular matrix or counterpart cells, followed by directional migration. (B) CD8⁺ T cells migrate to lymph nodes where they are primed by tumor- or virus-antigens presented by dendritic cells. These activated T cells are then recruited to cancerous or infected tissues and eliminate transformed or infected cells by secreting cytotoxic molecules including Granzymes. Immune cells have remarkable capabilities to adapt their mode of adhesion and migration to their surroundings. TCR, T cell receptor; MHC, Major histocompatibility complex.